The present application relates to an indirect conversion, radiation detector array with replaceable elements. It finds particular application in the field of computed tomography (CT) imaging utilized in medical, security, and/or industrial applications, for example. However, it also relates to other radiation modalities where an indirect-conversion detector array may be useful.
Today, CT and other imaging modalities (e.g., mammography, digital radiography, etc.) are useful to provide information, or images, of interior aspects of an object under examination. Generally, the object is exposed to radiation (e.g., X-rays, gamma rays, etc.), and an image(s) is formed based upon the radiation absorbed and/or attenuated by the interior aspects of the object, or rather an amount of radiation photons that is able to pass through the object. Typically, highly dense aspects of the object (or aspects of the object having a composition comprised of higher atomic number elements in the case of duel-energy) absorb and/or attenuate more radiation than less dense aspects, and thus an aspect having a higher density (and/or high atomic number elements), such as a bone or metal, for example, will be apparent when surrounded by less dense aspects, such as muscle or clothing.
Radiology imaging modalities generally comprise, among other things, one or more radiation sources (e.g., an X-ray source, Gamma-ray source, etc.) and a detector array comprised of a plurality of pixels that are respectively configured to convert radiation that has traversed the object into signals that may be processed to produce the image(s). As an object is passed between the radiation source(s) and the detector array, radiation is absorbed/attenuated by the object, causing changes in the amount/energy of detected radiation.
In some applications, such as in security and/or industrial applications, there is a trend toward high throughput imaging. For example, a baggage inspection apparatus at an airport may be designed to image 200 or more bags per hour. In such applications, the radiology imaging modality is typically configured to acquire information (e.g., X-ray information) sufficient to produce the image(s) while the object under examination is being continuously translated through the examination region.
There is also a trend in some applications, such as in security and/or industrial applications, for volume imaging, where a three-dimensional (3D) image of the object is generated. It will be appreciated that a 3D image typically provides substantially more detail about the object under examination than a two-dimensional (2D) image, which may improve automatic and/or manual threat detection, for example. To generate such a 3D image, the object is typically divided into a plurality of slices and each slice is viewed from a plurality of angles, typically by rotating the radiation source(s) and/or detector array about the object as it is being examined.
To generate a volumetric image of an object in a high throughput environment a large number of slices of the object typically have to be acquired concurrently. Therefore, the detector array must be large enough to accommodate examining numerous slices of the object concurrently. However, detector measurement systems (DMSS) for such imaging modalities present numerous challenges due to the number of detector pixels required, and therefore the number of channels necessary (e.g., which may be in the hundreds of thousands) to achieve a desired image resolution using such a large detector.
The advent of high integration measurement integrated circuits (ICs), which may comprise a plurality of channels per chip (e.g., such as 64, 128, 256, etc. channels per chip) (e.g., where respective channels are coupled to one pixel), allow the design of smaller self-contained elements that can be assembled into larger detector arrays. In U.S. Pat. No. 7,582,879, assigned to Analogic Corporation, one such self-contained module is described. As provided for therein, the elements, which may be referred to as tiles, are constructed of, among other things, a scintillator, a photodetector array, and an integrated circuit. Respective tiles are fully self-contained and may be coupled together to form what is referred to as a super module, and super modules may be coupled together to form the detector array. When the scintillator, photodetector array, integrated circuit, and/or another component of the module functions improperly, the tile can be replaced without having to replace the entire detector array, for example.
While the self-contained module described in U.S. Pat. No. 7,582,879 has proven effective, there are areas for improvement. For example, when a component of the tile functions improperly, the entire tile must be replaced. That is, individual components of the tile cannot be replaced.